2014 We have measured the mobility of positive ions in several gas mixtures frequently used in proportional and drift chambers, namely Ar-(OCH3)2CH2, Ar-(OCH3)2CH2-IsoC4H10, Ar-CH4, and Ar-CO2. In all gas mixtures considered, Blanc’s law of positive ion mobility has been verified, except for a very small methylal concentration in argon-isobutane-methylal. The law permits the calculation of ion ...

The isomers of the Man(7)GlcNAc(2) glycan obtained from bovine ribonuclease B have been characterized by ion mobility spectrometry-tandem mass spectrometry (IMS-MS/MS). In these experiments, [Man7 + 2Na](2+) precursors having different mobilities are selected by ion mobility spectrometry and analyzed by MS/MS techniques in an ion trap. The fragmentation spectra obtained for various precursor io...

Ion mobility instruments that utilize nitrogen as buffer gas are often preceded by an ion trap and accumulation region that also uses nitrogen, and for different inert gases, no significant effects upon performance are expected for ion mobility spectrometry (IMS) of larger ions. However, we have observed significantly improved performance for an ion funnel trap upon adding helium; the signal in...

A small subsurface ion mobility spectrometer (SS-IMS) was constructed and tested with several environmental contaminants to determine its potential for monitoring gaseous volatile organic compounds in the vadose zone. Trichloroethylene (TCE) and tetrachloroethylene (PCE) were detected and separated in IMS for the first time. Detection limits as low as 1 part per billion volume-to-volume (ppb(v)...